How to Accelerate Rail Signaling Commissioning: 5 Tips from Signaling Engineers

When a railway project moves to the commissioning stage, the countdown to the updated rail line launching begins. All interested parties start to closely monitor the project. If the testing stages run smoothly and the line is launched on time, this naturally adds credibility to the responsible company and affects the inflow into the rail industry. Despite this, companies often are unprepared for commissioning with all its bottlenecks that significantly delay the launch of the rail line, which alarms third-party observers. Why is this happening?

Commissioning is the final rehearsal before exploiting the rail line, where all the flaws present themselves. Nothing can be hidden there: if mistaken when ordering components — it is revealed at the factory; if initial documentation was not in order — this turns out in a moment. Generally, these are not failed tests, but shortcomings in the organization of the procedure forcing it to be postponed for weeks or even months.

Thus, how to run commissioning seamlessly to finish it on time? We at PSA have been commissioning rail signaling solutions for over 15 years and want to share the best practices on how to prepare for commissioning; to seamlessly carry it out. 

What Is Rail Signaling Commissioning and Why Is It So Challenging?

Commissioning ensures that all rail systems and equipment are designed, installed, tested, and configured, complying with the customer's specifications. It does not matter if only the wayside needs to be upgraded, or the rails and rolling stock are being redone. Commissioning always includes FAT (Factory Acceptance Testing) and SAT (Site Acceptance Testing). By this stage, we have all the equipment ready but not connected to the location. Commissioning is to test the system in real conditions, including extreme situations.

• During the FAT, signaling equipment is tested — without sparing. The factory testing team checks all kinds of rail signaling scenarios and even pulls the wires to test their reliability. This is to ensure that no component ever causes a dangerous failure. All functional tests are carried out in a simulation environment with conditional switches, circuits, and signals connected. Almost all the shortcomings in the equipment are detected — during the FAT and, as a rule, are eliminated on the spot or within one day.

• SAT involves the same actions but is performed in a real environment — in the field. Sometimes this procedure can be divided into integration tests and inspections, especially within complex projects, but the point is the same — to check the performance of the entire railway line with the updated equipment.

Malfunctions in the systems can be detected during testing — but 99% of commissioning delays occur through the human factor and problematic management as well. People do the assembly and installation, carry out support, and study documents. Therefore, this cannot be 100% reliable. Since it is unprofitable; and in some cases impossible to automate these processes, let us dwell on how to improve the management of rail projects.

Establish Surveys for Rail Signaling Documentation

The most common "brake" of the commissioning is discovered during the preparation for the SAT — when the newly-made equipment does not match the real field situation. This is due to outdated existing drawings of the station, which the design team is guided by when developing the wayside. It's natural that it was serviced for 30 or more years of the lines running. The components, circuits, and cables were replaced — which was forgotten to be reflected in the documentation.

In such cases, instead of starting tests, the specialist has to conduct unscheduled reconciliations and document each cable and circuit on location to redesign the newly made system. Count yourself fortunate if the design requires minor edits that delay the start of testing by one to two days, but in practice, it can take weeks.

The workable practice here is to conduct detailed surveys — verify the documentation and the real system on the location before starting hardware and software development. Bungalows, signals, and switches have to be photographed to give the designer a comprehensive view of the station. Surveys can be carried out by the customer themselves or using special staff, or the design team. The main thing is to provide access to all documentation and locations and have a high-resolution camera.

Coordinate Subcontractors

The more companies involved in the upgrade of the station, the more meticulous the management should be. If you are outsourcing rail signaling, communications, construction, track design, etc., to a different contractor. It is worthwhile to coordinate their work to increase their awareness of the whole project. If one party makes a mistake, it naturally leads to the whole system not performing accurately. Unfortunately, this is often found only during the SAT.

A good practice to avoid such surprises is to introduce cross-checking of each other's drawings by the subcontractors. In general, open access to all the working materials, including test results, by all the participants, helps reduce the amount of confusion in the future.

Extend the Independent Expertise for Rail Signaling

Thanks to the global adoption of independent testing teams, we hope that the problems that were overlooked during commissioning — are things of the past. However, since there is no single standard for realizing interlocking functionality, some rail signaling solutions are not performed optimally, which becomes obvious when the line is already running. Therefore, we consider it a successful practice to invite independent rail signaling designers as well — specialists from competing companies have their own experience. Firstly, it provides a fresh look at a wayside design ensuring we never miss the details. Secondly, it allows for finding an alternative solution that was proven to be more efficient. And the third is to adopt experience.

Think Over The Commissioning Approach

Companies often establish the weekend testing mode, which reduces costs but increases risks during the procedure. The rail line does not have to stop, which allows for money savings. However, the legacy and the new systems have to constantly be reconnected. Which often leads to issues — like malfunctions that appear during swinging back to the old system. Thus, it takes more time to recover the whole system operation.

The second option is to close the rail line until all the tests are done. A definite plus of this approach is safety. Also, there is no need to create additional temporary schemes to communicate with the old equipment. The obvious disadvantage is the financial side. Financial risks increase significantly with the postponement of the deadlines. For instance, if the station or line is planned to be closed for a week, every hour of its expansion brings about additional expenses. Therefore, evaluate the conditions precisely when deciding on the testing approach.

Introduce Overtimes

Even with perfect planning, there are still unpredictable issues that should be considered during commissioning. The sticking point at the FAT — is miscalculation when ordering the necessary equipment or its components. Such a mistake can extend the FAT by a couple of months — since the suitable equipment may be very specific, requiring extensive production time. Unfortunately, this mistake is hard to avoid since all the features for the equipment to order are defined after the design is complete. Considering this, it should be ordered at the beginning of the project.

For SAT, it is challenging to predict the aging of the material or troubles with the equipment onsite. For instance, the existing circuits may fail — or new equipment will be damaged during the installation process. It's useful to get complete info on the location to assess the impact of external factors. Therefore, decide on the necessary overtime.

Summing Up: Best Practices for Rail Signaling Commissioning

For the little oversights not to become a disaster during commissioning, we recommend preparing for the FAT and SAT before the start of the project. It is useful to:

• Make sure all the existing drawings you give to the subcontractors correspond to the real situation on the field.
• Ensure the joint work of all your contractors and request open access to their working documentation.
• Involve additional experts to witness the testing procedures to increase the quality of the work performed.
• Consider all possible factors before establishing the testing approach.
• Consider overtime for the unpredictable issues that are common for rail.

By entering these practices in advance, your commissioning activities will be carried out considerably smoother. Hopefully, commissioning will never become a bottleneck of your future projects.

About the Author: Julia Mitchell is Business Operations Manager at Professional Software Associates Inc. (PSA).